Afterbody of vessels



May 19, 1942. F. H. SELDEN AFTER-BODY OF VESSELS Filed Sept. 28, 1938 4 Sheets-Sheet l May 19, 1942.

F. H. SELDE N AFTER-BODY. OF VESSELS F'iled'Sept. 28, 1938 4 Sheets-Sheet 2 May 19, F. H S E AFTER-BODY OF VESSELS I,

Filed Sept. 28, 1938 4 Sheets-Sheet 3 wa z;

y 1942- F. H. SELDEN AFTER-BODY OF' VESSELS 4 Sheets-Sheet 4 Filed Sept. 28, 1938 Patented May 19, 1942 sm'ss PATENT OFFICE 2,283,291 AFTERBODY F VESSELS Folke Herbert Seldn, Langedrag, Sweden, as-

signor to Aktiebolaget Giitaverken, Goteborg, Sweden, a corporation ofSweden Application September 28, 1938, Serial No. 232,044

In Sweden October 2, 1937 3 Claims.

The present invention relates to improvements design of the rudder and pertaining parts of the after-body of vessels of the above mentioned and other types. 7 7

One object of the invention is to provide an after-body construction, which smoothly fits the above-mentioned large hub screws, and permits supervision and, for instance, adjustment of the propeller shaft bearing disposed at the screw as well as of the after-part of the propeller shaft without docking the ship.

A further object of the invention is to provide accessible for supervision, adjustment or the like from the interior of the vessel while the ship is in the water. Further objects and features of the invention are disclosed by the following specification and claims.

In the accompanying drawings some embodiments of the invention are illustrated by way of example.

an after-body construction, which has good stream-line shape, makes little resistance to the water and results in an efficient screw arrangement.

Another object of the invention is to make supervision, adjustment or the like of the interior of the rudder and/or such rudder bearings, which are situated outside the hull of the vessel and disposed at a rudder post, a stern post, a pivot or the like built out from the body of the ship, possible, while the ship lies in the water.

A still further object of the invention is to limit the damages, occurring upon grounding or the like, to the rudder, especially with free or partly free rudders, so that particularly the movability of the rudder is not so easily destroyed or impaired upon a light touch of the bottom or the like.

One feature of the invention consists in an after-body construction of the above mentioned type comprising a screw with a relatively large hub, the propeller shaft ahead of the screw being enclosed by a propeller sleeve or shell, which has such a large diameter, and has a propeller shaft bearing provided therein just ahead of the screw in such a manner, that said bearing is accessible from the interior of the propeller sleeve or shell, which is accessible from the interior of the hull of the vessel and sealed tightly from the Water surrounding the ship. A further feature of the invention consists in the propeller sleeve or shell, the screw hub and an extension of the propeller sleeve provided astern of the screw forming together a continuous'stream-line body tapering astern. A still further feature of the invention consists in the interior of the rudder and/or the external bearings of the rudder being Fig. 1 is a side view of theafter-body of a vessel provided with a central screw.

Fig. 2 is a longitudinal section of a modification of the after-bodyillustrated in Fig. 1.

Fig. 3 illustrates the after-body according to Fig. 2 as viewed from below.

Fig. 4 is a section on line IV-IV in Fig. 2 looking aft.

Fig. 5 is a horizontal section on a large scale of the lower rudder bearing of the embodiment according to Fig. 2 together with the pertaining parts of the after-body.

Fig. 6 is a vertical longitudinal section on line VIV1 in Fig. 5. V

Fig. 7 is a view from below of the after-body ofa twin screw vessel according to the invention.

Fig. 8 is a side view of the after-body illustrated in Fig. 7, and

'Fig. 9 is a view from below of the after-body of a further embodiment of a twin screw vessel according to the invention.

Throughout the drawings the same reference numerals are used to indicate equivalent parts.

In Figs. 2-6 the invention is illustrated as applied to a single screw vessel having a half free and semi-balanced rudder. The embodiment of the invention illustrated in Fig. 1 corresponds to the embodiment illustrated in Figs. 2-6 in all respects but the mounting of the rudder, which according to Fig. 1 is a non-free rudder supported by a bearing provided at an extension of the keel. I designates the hull of the vessel, 2 the rudder, 3 the portion of the propeller sleeve orshell disposed ahead of the screw, 4 the screw, and 5 the propeller shaft on the end of which the screw is secured by means of a nut 6. The propeller sleeve 3 comprises a stream-line sheet metal body or shell tapering continuously astern, welded to the hull l and fitting smoothly at its rear border to the hub portion of the screw 4. Said hub portion comprisesa central boss I, which by means of a web 8 is connected to a slightly tapering rim 9, to which the screw blades are secured. The rim 9, which tapers astern, fits smoothly to the propeller sleeve 3 ahead of the screw and to an extension I0 astern of the screw. Said extension is provided with a wall ll having an opening just in front of the nut 6, through which said nut is accessible for tightening or loosening before a scuttle l2 covering the opening has been secured or after removal of said scuttle. The propeller sleeve 3 is provided with internal reinforcing ribs l3 welded to the sleeve or shell and accommodates in its after-part a sheet metal support |4, upon which a bearing I5 is disposed just ahead of the screw, said bearing comprising, for instance, a journal or roller bearing. The bearing rests on the support I4 and is consequently carried by the propeller sleeve, which transmits the forces taken up by the bearing to the hull A similar bearing i6 is provided on a sheet metal support H in the fore portion of the propeller sleeve. At the stern end the propeller sleeve 3 is provided with a water tight bulkhead l8, which by means of a sealing ring I9 or the like of known construction seals against the central boss 'l of the hub of the screw but which may naturally be arranged to seal directly against the propeller shaft. Another water tight bulkhead is provided in the forward portion of the propeller sleeve 3 and seals against the propeller shaft 5 by means of a packing box 2| or the like. A water tight door or scuttle 22 is provided in the bulkhead 26. A water tight scuttle 23 may, if

. desired, be provided in the roof of the propeller sleeve instead of the door 22, through which the interior of the propeller sleeve is accessible for inspection, lubricating, adjustment or the like of the bearings l5 and IS," the propeller shaft 5 or the seals.

In the embodiments of the after-body illustrated in Figs. 1-8 a hollow body 25 is built out from the hull of the vessel astern of the screw aperture 24. At its lower end said pivot carries a stream-line sheet metal body ID, which fits smoothly to the screw hub with its fore end and forms a continuation astern of the screw of the stream-line propeller sleeve or shell 3. The propeller sleeve 3, the screw hub 9' and the extension l3 form together a body of continuous stream-line shape tapering astern and extending from the under water part of the after-body. In the embodiments illustrated in the drawings the generative line of said stream-line body makes an angle of about 8 with the propeller shaft. In the embodiments illustrated in Figs. 1, 2', 3, 7 and 8- the extension I0 is provided with a horizontal transversely directed curved edge 26 and the rudder 2 in Fig. 1 and in the embodiments illustrated in Figs. 2, 3, 7 and 8, in which the rudder is a half free rudder, is provided with a corresponding aperture 21. The extension ID or the rudder post may contain and carry a bearing for the propeller shaft provided astern of the screw. Said extension may furthermore be connected to the propeller sleeve or shell by means of stream-line bows 28, for instance as illustrated in Fig. 1. The extension It] contains a bearing 29 for the rudder stock 30, which extends through the extension and has an arm 3| connected to the steering gear secured on its upper end.

The rudder stock 30 in Fig. 2 is tubular and the semi-balanced rudder according to'Fig. 2 is a hollow sheet metal rudder. The rudder stock 30 may be of one piece construction or comprise several parts connected by suitable joints such as internal or external flanges 32 or 33, respectively, as indicated in Fig. 2 or by any other suitable means. A water tight bulkhead 34 is provided ahead of the rudder-stock 30 in the extension l0 and separates the sternmost portion of the extension H] from the interior of the hollow body 25. The body 25 has internal horizontal reinforcing plates 35 provided with openings 36 and communicates with the chamber 31 in the foremost portion of the extension l0 through an opening 38. The rear wall of the hollow body 25 is formed by a plate 39, the upper portion of which forms a bulkhead, which constitutes the front wall of a chamber 40 communicating with the water around the ship and preferably extending up to the level of the water line. The chamber 40 is covered by a plate 4|, which carries a thrust or cam bearing and sealing device 42. A rudder bearing 43 is provided on an intermediate bottom 44 near the upper end of the rudder-stock 30.

The rudder bearing 29, which is provided at about half the height of the rudder blade, takes up the radial forces from the rudder. The bearing cups of this bearing are pivotally mounted in the extension I0 and adjustable by means of screws 45 extending through the bulkhead 34 and consequently accessible from the chamber 31. In the embodiment of the invention illustrated in Fig. 2 the hollow body 25 and the chamber 3'! are given such dimensions that a man can go down through the body 25 and adjust the bearing 29.

One embodiment of an external rudder bearing such as, for instance, the bearing 29 in Fig. 2 is illustrated on a larger scale in Figs. 5 and 6. This bearing comprises two movable bearing parts 46 and 41, respectively, pivotally mounted on shafts 48 and 49, respectively, secured in the extension ID. A rear section 50 of the bearing is fixed in the extension H]. The bearing according to Figs. 5 and 6 is also provided with a fixed front section 5| connected with and forming a part of the bulkhead 34. The section 5|, however, may be dispensed with, if desired, and the swingable sections 46 and 4'! may then be elongated forwardscorrespondingly. The swingable parts 46 and 41 are connected at their front ends by a turn buckle including bolts 52 and 53 having right-hand threads and left-hand threads, respectively. The bolts 52 and 53 projecting through the bulkhead 34 are connected by a nut 54, the rotation of which causes the bolts and the bearing parts 46 and 41 to move toward or away from each other. 55 is a wearing sleeve provided on the rudder-stock 30. External rudder bearings of the type illustrated in Figs. 5 and 6 may naturally be provided in rudder constructions, in which the rudder is mounted on a rudder post or a stern post of a vessel and is of semi-balanced or non-balanced type.

' The side surfaces of the rudder according to Fig. 2 are formed by plates welded to each other at the stern edge 56 of the rudder and directly to the rudder-stock 30 as indicated by the dotted line 51. The rudder blade is internally reinforced by means of webs 58 provided with openings 59 and welded to the side plates and the other parts of the rudder. The rudder may also be reinforced by means of internal vertical plates or other reinforcing means. The rudder-stock 30 is open at the upper and lower ends so that a man, if the rudder-stock is given sufficiently large dimensions, may go down through the rudder-stock and get into the interior of the rudder for inspection, draining or the like. The part of the rudder-stock 30, which is situated at the upper portion of the rudder blade may also be provided with openings 60, through which the interior of the upper portion of the rudder blade is more accessible.

The lower portion 6| of the free rudder part,

which is most exposed to grounding or thelike, is made of considerably thinner sheet metal than the rest of the rudder as obvious from Fig. 2. The web 58 in this portion of the rudder is also made of thinner plate than the webs 58 in' the rest of the rudder. This weakening of the lower portion 6| of the rudder results in that, upon a moderate impact at this portion of the rudder, which is the portion most exposed to damage upon grounding with the stern of the ship, the thin sheet material of the rudder portion BI gives away and is more or less demolished without the parts of the rudder made of heavier plate or the parts carrying the rudder being damaged. Furthermore, in the embodiment'illustrated in Fig. 2 the two bottom compartments 62 and 63 of the rudder are made of light plate, whereas the adjacent compartment 64 bordering directly on the extension I is made by heavier material. Thus the risk is reduced that the rudder may catch on the extension [0 upon deformation.

The embodiment above described and illustrated in Figs. 1-6 should only be considered as an example and the details of the invention may naturally be modified in different ways within the scope of the following claims. vention may also be applied to the after-body of vessels having several screws and/or several rudders. Figs. '7, 8 and 9 illustrate the invention as applied to twin screw vessels, Figs. 7 and 9 being views from below of the after-body of two such vessels and Fig. 8 a side view of the afterbody illustrated in Fig. '7. In the embodiment according to Figs. 7 and 8, which is almost a duplication of the arrangement according to Fig. 2, a stream-line shell 3 projects astern at each side of the under water part of the after-body of the vessel and is carried by a downwardly projecting stream-line portion 69. Left and right-hand screws 4, 4 are provided on the larboard and starboard side of the vessel, said screws being provided with tapering hubs 9 and an extension l0 being disposed astern of each screw. The propeller sleeves 3, hubs 9 and extensions II] in this embodiment form stream-line bodies tapering astern with a taper of 8 with respect to the propeller shaft or the centre line of said stream-line bodies. A semi-balanced and half free rudder 2 is provided astern of each screw in the embodiments according to Figs. '7 and 8. In Fig. 9 an arrangement is illustrated, in which a single totally free and fully balanced rudder B is centrally disposed astern of and between the two screws 4. In this case extensions 66 of substantially conical shape are provided astern of each screw 4, which extensions may be secured to the hubs 9 of the screws or carried by suitable stream-line pivots projecting downwardly from the hull of the ship astern of the screws. Obviously the invention may also be applied to after-body constructions of ships having other screw or rudder arrangements than those above described. In the embodiment illustrated in Figs.- 2-4 a keel 61 having a stream-line end portion is provided underneath the propeller sleeve 3. I

While I have shown and described several embodiments of my invention, it is to be understood that this has been done for purposes of illustration only and that the scope of my invention is not to be limited thereby, but is to be determined by the appended claims.

Thus the in- What I claim is:

1. man after-body construction of a vessel, a propeller shaft, a propeller screw secured on the after part of said shaft, said screw having a conical hub tapering astern and having an average diameter at least one quarterthat of the blade sleeve transmitting the forces imposed on said bearing to said hull, means providing access by a man from the interior of said hull to the interior of said sleeve, the sleeve itself having surficient width to permit access by the man to said bearing, means forming a substantially conical extension of said hub, a hollow body communicating with the interior of said hull and extending downwardly therefrom to support said extension, a rudder astern of said hollow body and a bearing for said rudder carried by said hollow body and accessible for adjustment from the interior thereof.

2. In an after-body construction of a vessel, a propeller shaft, a propeller screw secured on the after part of said shaft, said screw having a conical hub tapering astern and having an average diameter at least one quarter that of the blade diameter of the screw, a substantially conical sheet metal sleeve secured to the hull of said vessel and enclosing a portion of said shaft forward of the screw and tapering astern to conform to said tapered hub, a, propeller shaft bearing provided in and carried by the after end of said sleeve immediately forward of the screw,

said sleeve transmitting the forces imposed on said bearing to said hull, means providing access by a man from the interior of said hull to the interior of said sleeve, the sleeve itself having suili-cient width to permit access by the man to said bearing, means forming a substantially conical extension of said hub, a hollow body communicating with the interior of said hull and extending downwardly therefrom to support said extension, a semi-balanced and semi-free rudder astern of said hollow body having a rudder blade formed with an aperture corresponding to said extension, and a bearing for said rudder carried by said hollow body at approximately half the height of said blade and accessible for adjustment from the interior of said hollow body.

3. In an after-body construction of a vessel, a propeller shaft, a propeller screw secured on the after part of said shaft, a hub therefor having an average hub diameter of more than one fourth of the blade diameter of said screw, a sheet metal sleeve secured to the hull of the vessel and enclosing a portion of the propeller shaft forward of the screw and shaped substantially in the form of a truncated cone tapered toward the stern of the vessel to conform with said hub, an after end wall in said sleeve, bearing means supporting said shaft in the after end of said sleeve immediately forward of said end wall, and means independent of said bearing means carried by said wall for sealing said wall water tight with respect to said shaftwhereby access to said bearing means may be readily attained at all times. FOLKE HERBERT SELDEN. 

